Geothermal Heating and Cooling Systems

Geothermal heating and cooling uses the relatively constant temperature of the earth to heat and cool homes and businesses with 40% to 70% less energy than conventional systems. In winter, the relative warmth from the ground or ground water is transferred to the building, and in summer the process is reversed and the heat of the building is transferred to the earth or ground water.

Geothermal heating and cooling systems can be divided into two broad classes: open-loop systems and closed-loop systems. An open-loop system withdraws ground water from a well, passes it through a heat exchange system, and discharges the temperature-altered water either back to the ground via a return well or to surface water. A closed-loop system circulates a heat transfer fluid (usually water with an antifreeze additive) through a loop or multiple loops of piping installed below ground or within a surface water body. A closed-loop system does not involve the withdrawal of ground water.

Open Loop Geothermal System
Closed Loop Geothermal System

For more information on the installation, operation, and decommission of geothermal heating and cooling systems in Ohio:

For additional information, contact the Ohio EPA, Division of Drinking and Ground Waters by e-mail at or phone at (614) 644-2752.